Various outdoor activities, such as picnics, overnight camping trips, etc., are enjoyed by many persons. Many such activities, including those mentioned above, involve the preparation of meals, which foods generally must be transported and stored until preparation and consumption. While it is certainly possible to use processed foods which require no refrigeration prior to preparation, consumers have recently become more and more aware of the potential hazards of consuming foods which should be refrigerated.
Accordingly, relatively simple and inexpensive ice chests have become popular for the storage of foods requiring refrigeration, with ice in block, cube, or other form being used as the cooling agent where no electricity is available to power a mechanical unit. Such a cooling system is reasonably effective for a few hours, depending upon the ambient temperature, sunlight, the amount of time the cooler is open, thermal efficiency of the cooler, etc. However, at best, it is unlikely that the use of ice and an ice chest would be capable of preserving food longer than overnight at best, in typical summertime conditions in a temperate climate.
The above limitations would preclude the use of any foods requiring refrigeration for more than an overnight trip, unless more ice were available. This may not be the case, where a three day or longer trip is made into a primitive area, where no facilities are available. Thus, persons wishing to keep perishable foods for more than a day or so, must leave their camping site and seek out a place where they can purchase additional ice in order to keep such foods safely. The only safe alternative is to forgo such perishable foods, and take processed or canned foods which do not require refrigeration. Such foods may be seen as less palatable to many persons, and the exclusive use of such foods for a few days, may well lessen the enjoyment of the camping experience for those persons.
Thus, a need will be seen for a manually operated refrigeration apparatus, which is capable of keeping a container chilled for an indefinitely long period of time with periodic operation. The apparatus should be capable of chilling the interior of an insulated chest to a freezing temperature if desired, and to a temperature between thirty and forty degrees Fahrenheit in order to provide refrigeration of foods which may be contained within the chest. The device must require no external electrical or other power, other than manual (hand or foot operated) input from time to time, in order to compress the refrigerant contained within the device. The apparatus must be readily adaptable to use with a modified ice chest of any suitable configuration, with the ice chest containing cooling coils for the circulation of refrigerant therein, as required. Finally, the device must be economical, portable, easily used, and operable with refrigerants which are environmentally safe.